Shed Roof Rafter Design

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

Shed roof rafter design.

How to frame a gambrel shed roof. Here we have a wood framed gable roof. Much depends on the structure size and the desired attic loft or headroom. Easy rafters is designed to calculate shed roofs that are framed to a ledger board nailed against a vertical wall not freestanding shed roofs supported by walls at both ends.

The rule of thumb is that the gusset should be twice the width of the wood you use for your rafters. The roof on this shed is a 4 in 12 slope which makes it a 18 and one half degree angle on the board ends. Half building width minus 1 2 ridge thickness. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through.

A simple gable shed roof is often built using 2 4 or 2 6 lumber for the rafters and 2 4 for the collar ties. A gable roof for a shed can be built with rafters with a 1 6 ridge board or using trusses. The saltbox roof design offer lots of character and charm to the backyard. Allow for ridge thickness when determining rafter run to outer wall.

Let s consider a basic gable wood roof framing design. Now you have extra 2 4 hanging over the bottom chord. This will allow them to join and form the peak of the roof and let the other end fit nicely at the 60 degree angle of the bottom chord. So use your speed square and measure your angle.

You are going to cut out triangles that will cover the apex of each set of rafters. A shed roof slopes in one direction only. The ridge end of the rafter and often the eve end will need to be cut to the angle of the roof slope. Measure your rafter boards for your preferred roof style and pitch.

The exact length and angle of your rafters will depend on the overall size of your shed as well as the style and slope you ve chosen. The rafters on a steeply sloped roof for instance will be much longer and have more end cuts than those on a flat roof. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. For an 8 10 shed one sheet of plywood should be fine.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. It is possible to calculate a birdsmouth near the top of the rafter for a freestanding shed roof by checking the kneewall checkbox and entering a setback for the kneewall that positions the upper birdsmouth in the desired location. Do you want to build a shed that makes a perfect garden shed. See rafter run to outer wall calculator below.

Continuing on from part 3. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. Then cut the rafter angle at 30 degrees for two 2 4 s.